From b0bf224bb148f08d362ff6ee1bb17a47ac0b54b7 Mon Sep 17 00:00:00 2001
From: Ian Li <techotaku@users.noreply.github.com>
Date: Sat, 25 Nov 2023 15:40:05 +0800
Subject: [PATCH] feat: support LOGIN as SMTP authentication method.

---
 common/constants.go                         |  1 +
 common/email.go                             | 35 ++++++++++++++++++++-
 i18n/en.json                                |  1 +
 model/option.go                             |  3 ++
 web/default/src/components/SystemSetting.js | 10 +++++-
 5 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/common/constants.go b/common/constants.go
index 9ee791df..45dc9ad7 100644
--- a/common/constants.go
+++ b/common/constants.go
@@ -62,6 +62,7 @@ var SMTPPort = 587
 var SMTPAccount = ""
 var SMTPFrom = ""
 var SMTPToken = ""
+var SMTPAuthLoginEnabled = false
 
 var GitHubClientId = ""
 var GitHubClientSecret = ""
diff --git a/common/email.go b/common/email.go
index b915f0f9..7df0d088 100644
--- a/common/email.go
+++ b/common/email.go
@@ -4,12 +4,39 @@ import (
 	"crypto/rand"
 	"crypto/tls"
 	"encoding/base64"
+	"errors"
 	"fmt"
 	"net/smtp"
 	"strings"
 	"time"
 )
 
+type loginAuth struct {
+	username, password string
+}
+
+func LoginAuth(username, password string) smtp.Auth {
+	return &loginAuth{username, password}
+}
+
+func (a *loginAuth) Start(_ *smtp.ServerInfo) (string, []byte, error) {
+	return "LOGIN", []byte(a.username), nil
+}
+
+func (a *loginAuth) Next(fromServer []byte, more bool) ([]byte, error) {
+	if more {
+		switch string(fromServer) {
+		case "Username:":
+			return []byte(a.username), nil
+		case "Password:":
+			return []byte(a.password), nil
+		default:
+			return nil, errors.New("unknown command from server during login auth")
+		}
+	}
+	return nil, nil
+}
+
 func SendEmail(subject string, receiver string, content string) error {
 	if SMTPFrom == "" { // for compatibility
 		SMTPFrom = SMTPAccount
@@ -37,7 +64,13 @@ func SendEmail(subject string, receiver string, content string) error {
 		"Date: %s\r\n"+
 		"Content-Type: text/html; charset=UTF-8\r\n\r\n%s\r\n",
 		receiver, SystemName, SMTPFrom, encodedSubject, messageId, time.Now().Format(time.RFC1123Z), content))
-	auth := smtp.PlainAuth("", SMTPAccount, SMTPToken, SMTPServer)
+
+	var auth smtp.Auth
+	if SMTPAuthLoginEnabled {
+		auth = LoginAuth(SMTPAccount, SMTPToken)
+	} else {
+		auth = smtp.PlainAuth("", SMTPAccount, SMTPToken, SMTPServer)
+	}
 	addr := fmt.Sprintf("%s:%d", SMTPServer, SMTPPort)
 	to := strings.Split(receiver, ";")
 
diff --git a/i18n/en.json b/i18n/en.json
index 774be837..4b65613c 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -330,6 +330,7 @@
   "通常和邮箱地址保持一致": "Usually consistent with the email address",
   "SMTP 访问凭证": "SMTP Access Credential",
   "敏感信息不会发送到前端显示": "Sensitive information will not be displayed in the frontend",
+  "使用 SMTP LOGIN 认证方式": "Use LOGIN as SMTP authentication method",
   "保存 SMTP 设置": "Save SMTP Settings",
   "配置 GitHub OAuth App": "Configure GitHub OAuth App",
   "用以支持通过 GitHub 进行登录注册": "To support login & registration via GitHub",
diff --git a/model/option.go b/model/option.go
index 20575c9a..b665b6f9 100644
--- a/model/option.go
+++ b/model/option.go
@@ -47,6 +47,7 @@ func InitOptionMap() {
 	common.OptionMap["SMTPPort"] = strconv.Itoa(common.SMTPPort)
 	common.OptionMap["SMTPAccount"] = ""
 	common.OptionMap["SMTPToken"] = ""
+	common.OptionMap["SMTPAuthLoginEnabled"] = strconv.FormatBool(common.SMTPAuthLoginEnabled)
 	common.OptionMap["Notice"] = ""
 	common.OptionMap["About"] = ""
 	common.OptionMap["HomePageContent"] = ""
@@ -159,6 +160,8 @@ func updateOptionMap(key string, value string) (err error) {
 			common.DisplayInCurrencyEnabled = boolValue
 		case "DisplayTokenStatEnabled":
 			common.DisplayTokenStatEnabled = boolValue
+		case "SMTPAuthLoginEnabled":
+			common.SMTPAuthLoginEnabled = boolValue
 		}
 	}
 	switch key {
diff --git a/web/default/src/components/SystemSetting.js b/web/default/src/components/SystemSetting.js
index 7b34ce5b..bcce7737 100644
--- a/web/default/src/components/SystemSetting.js
+++ b/web/default/src/components/SystemSetting.js
@@ -16,6 +16,7 @@ const SystemSetting = () => {
     SMTPAccount: '',
     SMTPFrom: '',
     SMTPToken: '',
+    SMTPAuthLoginEnabled: '',
     ServerAddress: '',
     Footer: '',
     WeChatAuthEnabled: '',
@@ -72,6 +73,7 @@ const SystemSetting = () => {
       case 'TurnstileCheckEnabled':
       case 'EmailDomainRestrictionEnabled':
       case 'RegisterEnabled':
+      case 'SMTPAuthLoginEnabled':
         value = inputs[key] === 'true' ? 'false' : 'true';
         break;
       default:
@@ -103,7 +105,7 @@ const SystemSetting = () => {
     }
     if (
       name === 'Notice' ||
-      name.startsWith('SMTP') ||
+      (name.startsWith('SMTP') && !name.endsWith('Enabled')) ||
       name === 'ServerAddress' ||
       name === 'GitHubClientId' ||
       name === 'GitHubClientSecret' ||
@@ -411,6 +413,12 @@ const SystemSetting = () => {
               checked={inputs.RegisterEnabled === 'true'}
               placeholder='敏感信息不会发送到前端显示'
             />
+            <Form.Checkbox
+              checked={inputs.SMTPAuthLoginEnabled === 'true'}
+              label='使用 SMTP LOGIN 认证方式'
+              name='SMTPAuthLoginEnabled'
+              onChange={handleInputChange}
+            />
           </Form.Group>
           <Form.Button onClick={submitSMTP}>保存 SMTP 设置</Form.Button>
           <Divider />